[PATCH v2 3/5] clk: mxl: Avoid disabling gate clocks from clk driver

[Rahul Tanwar]

In MxL's LGM SoC, gate clocks are supposed to be enabled or disabled
from EPU (power management IP) in certain power saving modes. If gate
clocks are allowed to be enabled/disabled from CGU clk driver, then
there arises a conflict where in case clk driver disables a gate clk,
and then EPU tries to disable the same gate clk, then it will hang
polling for the clk gated successful status.

To avoid such a conflict, disable gate clocks enabling/disabling from
CGU clk driver. But add a GATE_CLK_HW flag to control this in order to
be backward compatible with other SoCs which share the same CGU IP but
not the same EPU IP.

Signed-off-by: Rahul Tanwar <rtanwar@xxxxxxxxxxxxx>
---
 drivers/clk/x86/clk-cgu.c | 32 ++++++++++++++++++++++++--------
 drivers/clk/x86/clk-cgu.h |  1 +
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/x86/clk-cgu.c b/drivers/clk/x86/clk-cgu.c
index 1f7e93de67bc..d24173cfe0b0 100644
--- a/drivers/clk/x86/clk-cgu.c
+++ b/drivers/clk/x86/clk-cgu.c
@@ -258,8 +258,12 @@ static int lgm_clk_gate_enable(struct clk_hw *hw)
 	struct lgm_clk_gate *gate = to_lgm_clk_gate(hw);
 	unsigned int reg;
 
-	reg = GATE_HW_REG_EN(gate->reg);
-	lgm_set_clk_val(gate->membase, reg, gate->shift, 1, 1);
+	if (gate->flags & GATE_CLK_HW) {
+		reg = GATE_HW_REG_EN(gate->reg);
+		lgm_set_clk_val(gate->membase, reg, gate->shift, 1, 1);
+	} else {
+		gate->reg = 1;
+	}
 
 	return 0;
 }
@@ -269,8 +273,12 @@ static void lgm_clk_gate_disable(struct clk_hw *hw)
 	struct lgm_clk_gate *gate = to_lgm_clk_gate(hw);
 	unsigned int reg;
 
-	reg = GATE_HW_REG_DIS(gate->reg);
-	lgm_set_clk_val(gate->membase, reg, gate->shift, 1, 1);
+	if (gate->flags & GATE_CLK_HW) {
+		reg = GATE_HW_REG_DIS(gate->reg);
+		lgm_set_clk_val(gate->membase, reg, gate->shift, 1, 1);
+	} else {
+		gate->reg = 0;
+	}
 }
 
 static int lgm_clk_gate_is_enabled(struct clk_hw *hw)
@@ -278,8 +286,12 @@ static int lgm_clk_gate_is_enabled(struct clk_hw *hw)
 	struct lgm_clk_gate *gate = to_lgm_clk_gate(hw);
 	unsigned int reg, ret;
 
-	reg = GATE_HW_REG_STAT(gate->reg);
-	ret = lgm_get_clk_val(gate->membase, reg, gate->shift, 1);
+	if (gate->flags & GATE_CLK_HW) {
+		reg = GATE_HW_REG_STAT(gate->reg);
+		ret = lgm_get_clk_val(gate->membase, reg, gate->shift, 1);
+	} else {
+		ret = gate->reg;
+	}
 
 	return ret;
 }
@@ -315,7 +327,8 @@ lgm_clk_register_gate(struct lgm_clk_provider *ctx,
 	init.num_parents = pname ? 1 : 0;
 
 	gate->membase = ctx->membase;
-	gate->reg = reg;
+	if (cflags & GATE_CLK_HW)
+		gate->reg = reg;
 	gate->shift = shift;
 	gate->flags = cflags;
 	gate->hw.init = &init;
@@ -326,7 +339,10 @@ lgm_clk_register_gate(struct lgm_clk_provider *ctx,
 		return ERR_PTR(ret);
 
 	if (cflags & CLOCK_FLAG_VAL_INIT) {
-		lgm_set_clk_val(gate->membase, reg, shift, 1, list->gate_val);
+		if (cflags & GATE_CLK_HW)
+			lgm_set_clk_val(gate->membase, reg, shift, 1, list->gate_val);
+		else
+			gate->reg = 1;
 	}
 
 	return hw;
diff --git a/drivers/clk/x86/clk-cgu.h b/drivers/clk/x86/clk-cgu.h
index 0aa0f35d63a0..73ce84345f81 100644
--- a/drivers/clk/x86/clk-cgu.h
+++ b/drivers/clk/x86/clk-cgu.h
@@ -197,6 +197,7 @@ struct lgm_clk_branch {
 /* clock flags definition */
 #define CLOCK_FLAG_VAL_INIT	BIT(16)
 #define MUX_CLK_SW		BIT(17)
+#define GATE_CLK_HW		BIT(18)
 
 #define LGM_MUX(_id, _name, _pdata, _f, _reg,		\
 		_shift, _width, _cf, _v)		\
-- 
2.17.1